Objective. To determine the major source of eicosanoid release in arthritic joint tissues and to examine the modulation of this release by indomethacin and diclofenac.
Methods. Release of prostaglandin E, (PGE,), 6-keto-PGF1,, leukotriene B, (LTB,), and LTC, was measured in supernatants of synovial tissue, cartilage, and bone incubates from patients with osteoarthritis, active rheumatoid arthritis (RA), inactive RA, and pseudogout. Radioimmunoassay (RIA) was used to determine the levels of the eicosanoids.
Results. Addition of the divalent cation ionophore A23187 resulted in significant release of all eicosanoids measured from synovial tissue, but not from cartilage, cortical bone, or cancellous bone. PG release was significantly inhibited by the addition of indomethacin or diclofenac at either lo-' moleshiter or lo-' moles/liter. The amount of LTC, released from cartilage and bone was only slightly above the detection limit of the RIA, whereas large amounts were released from synovial tissue. Neither indomethacin nor diclofenac had an effect on LTC, release. LTC, release from synovial tissue of patients with inactive RA was significantly decreased in comparison with the levels from synovial From the